Improve the speed of blend8 on AVR by 20-30%
Improve the speed of blend8 on AVR by 20-30%

The SCALE8_FIXED version of blend8 uses the formula

  result = (A*(255-amountOfB) + A + B*amountOfB + B) >> 8

However, by rearranging this to

  result = (256*A + B - A*amountOfB + B*amountOfB) >> 8

We can save 4 or 5 cycles (depending on how the optimiser sets up a and b inputs for that extra cycle)

This formula rearrangement may be advantageous for the C implementation too, but I haven't tried that.

FastLED/FastLED,FastLED/FastLED,FastLED/FastLED,FastLED/FastLED